Ford Explorer 2015 has humming sound coming from left rear I believe,bought last December 2022. Decide to buy new set of tires . Balanced and aligned of course but humming is still there. Diagnosed at tire shop saying I need new hub assembly. …800$. Second opinion mechanic says nothing wrong with bearing , hub , etc. Any advice ???
Wait an see if it gets worse. A bad bearing will get worse as miles pile up. The hum will become a growl.
I tend to believe the mechanic, not the tire shop. If you think it might be the tire, move it to the front and listen.
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Can the second mechanic say where the sound is coming from?
If not, then I would follow the tire shop’s suggestion.
Tester
Yep, easy and cheap to tell if it’s the tire, move it to the front.
So apparently , the mechanic had moved the tire to the front and I’m still hearing the sound coming front the back .
Ok, not tires. There are mechanics with listening tools that can trace noises and pinpoint locations. This is, of course after the mechanical bits in that corner are examined.
So maybe we should get a third opinion?? Like from a Ford Dealership? We have a Hub Assembly Part , and not sure if we should return it.
Have you noticed if the sound changes when cornering in either direction?
Tester
If it didn’t come from Ford, return it. Buy an OE Ford part.
You could get a second opinion but it does not have to come from a dealer.
Sound may get louder yes …but not 100%.
Before replacing any parts, I would remove the drain plug on the rear differential and see if there’s any metal debris on the magnet.
Sometimes rear differential noises can sound like an axle bearing.
Tester
I was thinking the rear differential as well. It could simply be low on fluid back there. Better shops will have a gadget called “chassis ears” . They’ll attach it to the area of interest, set up the microphones. and switch microphones as they drive the car, to narrow down where the sound is coming from. No need to guess whether it is the differential or one of the wheel hubs in other words.
OP, are you noticing any weird-looking tread-wear patterns on the rear tires?
No the tires are brand new. We started with replacing tires to see if it would fix the problem…but still hear humming/soft thumping in rear driver’s side when driven. The rear left tire was exchanged with left front tire to see if that made a difference but it has not. So not the tires.
A thumping sound coming from the left/rear that’s proven to not be the tire, my first suspect would be something amiss w/ the suspension system for that wheel. For a humming sound, first m suspect would be the brakes or wheel bearing on that wheel. You may have to ignore the second shop opinion, bite the bullet and replace the wheel bearing which I presume means replacing the hub on your configuration. It’s pretty common by reports here that’s the only way to prove this sort of noise is caused by the wheel bearing, as a bad bearing can still test ok, no play, no noise, on the shop lift.
Before replacing the hub, good idea to ask your shop to carefully inspect the suspension system and brakes, and make sure nothing is rubbing on either the wheel or that brake drum/disc.